Proportioning pump



April 14, 1964 Q w g s op 3,128,717

PROPORTIONING PUMP Filed Aug. 1, 1961 I N VEN TOR. Eda/1'77 CZ Wzlf/wpf United States Patent 3,128,717 PRGPORTIONING PUMP Edwin C. Weiskopt, New York, N.Y., assignor to Technicon Instruments Corporation, Chauncey, N.Y., a corporation of New York Filed Aug. 1, 1961, Ser. No. 128,5?0 7 Claims. (Cl. 103-149) This invention relates to pumps of the compressible tube type especially useful in simultaneously pumping a plurality of fluids in predetermined relative proportions or at predetermined flow rates.

In fluid pumps of the type shown and described, for example, in US. Patent Nos. 2,893,324 and 2,935,028 issued on July 7, 1959, and May 3, 1960, respectively, the pump includes a plurality of resiliently flexible tubes which are disposed laterally of each other for the delivery of a plurality of fluids in predetermined relative proportions. The tubes have substantially the same Wall thickness so that all of the tubes can be closed simultaneously at points intermediate their lengths, respectively, along a transverse line. The pump includes a platen and a plurality of rollers which are engageable with the tubes for simultaneously compressing the tubes progressively along their lengths against the surface of the platen for the pumping operation.

Pursuant to one of the objects of the invention, means are provided for increasing the tube closing pressure of the rollers on the tubes without creating excessive pressure on the walls of the tubes thereby avoiding any detrimental eilects on the tubes which might otherwise occur because of the increased closing pressures.

Another object is to provide means and a method for modifying existing pumps of the type indicated to provide increased tube closing pressures of the rollers on the tubes in a relatively simple manner and Without adversely affecting the pump tubes.

A further object is to provide a proportioning pump of the type indicated of generally improved construction.

The above and other objects, features and advantages of this invention will be more fully understood from the following description of the invention considered in connection with the accompanying drawings which are illustrative of the presently preferred embodiment of the invention.

In the drawings:

FIG. 1 is a top plan view, with parts omitted, of a pump according to the present invention;

FIG. 2 is a front elevational view of part of the pump;

FIG. 3 is a sectional view, on a larger scale, taken on line 33 of FIG. 1;

FIG. 4 is a perspective view of part of the pump; and

FIG. 5 is a perspective view of a spring member for the pump.

Referring now to the drawings in detail, the pump it) comprises a base support 12 which mounts a platen 14 on which the resiliently flexible tubes 16 of the pump are disposed for operation by the pump tube compressing mechanism 18 which is suitably driven by a motor, not shown. The platen is spring loaded and for this purpose a pair of laterally spaced compression springs 26) is mounted on the top of the base support 12, near each end of the platen, and engages the undersurface of the platen for biasing the platen upwardly toward the compressing mechanism. The compressing mechanism comprises a plurality of longitudinally spaced transversely extending pressure rollers 22 whose ends are connected to the links of laterally spaced sprocket chains 24 for movement of the rollers longitudinally of the tubes for the pumping operation. The tubes 16 are laterally disposed of each other and extend longitudinally of the platen and are supported on the upper surface 2% thereof.

The tubes are retained in position on the platen by the end blocks 28 and 3 1) which are removably mounted on the platen and retained in position on the platen by the corner pins 32. The tubes have substantially the same wall thicknesses so that all of them can be closed simultaneously at points intermediate their lengths, respectively, along a common transverse line by engagement of the rollers with the tubes along said transverse line. The tubes may be of diiferent inside diameters so that different quantities of fluid can be pumped through the respective tubes and it Will be observed that during operation of the pump a plurality of different fluids of different quantities, respectively, may be pumped simultaneously. The platen is provided with an inclined pressure relieving portion 34 in order that the fluid pressure in the tubes may be gradually decreased as the forward roller commences to disengage the tubes thus avoiding an abrupt decrease in pressure which might otherwise occur.

Pursuant to the invention, means are provided for increasing the tube closing pressure of the rollers on the tubes without creating excessive pressures on the walls of the tubes, thereby avoiding any detrimental effects which might otherwise occur, as for example decreased tube life, stretching of the tubes or snaking, irregular pumping action, etc. A pair of longitudinally extending laterally spaced roller engaging members 36 is mounted on the tube supporting surface 26 of the platen 14 along the side edges thereof. The members are mounted on said side edges by removing the end blocks 28 and 3t) and inserting the ends of the members on the corresponding pins 32, the ends of the members being provided with apertures 35$ for this purpose. It is to be noted that the longitudinal cross sectional contour of the members is the same as the longitudinal cross sectional contour of the platen and the undersurface of the members is in surface-to-surface contact with the tube supporting surface 26 of the platen along the side edges thereof. The thickness of the members is equal to about twice the thickness of the Walls of the tubes or slightly less than this to insure complete closing of the tubes. The ends of the rollers engage the upper surfaces 40 of the members so that the rollers, during engagement of the tubes, are spaced from the surface 26 of the platen a distance equal to the thickness of the members 36, thereby avoiding any excessive pressures or squeezing of the walls of the tubes. Members 36 are retained in position on the pins 32 by the tube retaining end blocks 28 and 30.

The spring pressure of the platen against the tubes during the compression action of the rollers can be increased without creating any excessive pressures on the walls of the tubes because of the provision of members 36 so that a greater closing pressure of the rollers on the tubes can be provided. The spring pressure can be increased in either of two Ways; by providing heavier springs 20 or by providing additional spring members 42 which may be inserted between the existing springs 20, at each end of the platen, in lateral alignment with said existing springs. The additional spring forces provided by spring members 42 result in an increase in the pressure applied by the rollers 22 on the tubes for closing the tubes, but the pressure is not applied to the walls of the tubes because of members 36.

As herein shown, spring members 42 comprise a pair of spring retainers 44 of generally U-shape with the legs 46 of each retainer extending in opposite directions and leg interconnecting part 48 of each retainer being in confronting relation with the interconnecting part of the other retainer and positioned between the legs of the retainer. The ends of the legs are provided with reflexed portions 50 which provide retaining means for the compression spring 52. It will be apparent that as the spring member is compressed, the leg connecting parts 48 of the retainers move away from each other in the space between the legs 46 of the other retainer. Each spring member may be easily inserted in the space between the top of base support 12 and the bottom of platen 14 and the resilience of the spring member retains it in position.

The present invention may be used to modify existing pumps to provide increased tube closing pressure by mounting roller engaging members 36 on the platen, as previously described, and by inserting the spring members 42 between the platen and the base support. New pumps may also be provided with members 36 or the equivalent structure and with spring members 42 or spring 20 hav ing greater spring force.

While members 36 have been shown as being separate from the end blocks 23 and 30, it will be understood that they may be fixedly or removably mounted to the end blocks to form a frame whose ends are the end blocks and whose sides are members 36 and this frame, as an integral unit, can be mounted on the platen 14.

While I have shown and described the preferred embodiment of my invention, it will be understood that the invention may be embodied otherwise than as herein specifically illustrated or described, and that certain changes in the form and arrangement of parts and in the specific manner of practicing the invention may be made without departing from the underlying ideas or principles of this invention within the scope of the appended claims.

What is claimed is:

1. In a pump having a plurality of resiliently flexible pump tubes disposed laterally of each other for the delivery of a plurality of fluids in predetermined relative proportions, said tubes having substantially the same wall thickness so that all of said tubes can be compressed and simultaneously closed at points intermediate their lengths, respectively, along a common transverse line for the pumping operation, and means including a spring loaded platen having a pump tube supporting surface and a plurality of rollers engageable with said tubes for simultaneously compressing the tubes progressively along their lengths against said surface of said platen for the pumping operation; a pair of laterally spaced members mounted on said platen, said members having roller engaging surfaces spaced from said surface of said platen a distance equal to approximately twice the wall thickness of said tubes for limiting the position of said rollers relative to the surface of said platen during the closed condition of said tubes and thereby limiting the compression load of said rollers on said tubes when said tubes are .closed during said pumping operation, and means for providing additional spring pressure on said platen for increasing the tube closing pressure of said rollers on said tubes.

2. In a pump having a plurality of resiliently flexible pump tubes disposed laterally of each other for the delivery of a plurality of fluids in predetermined relative proportions, said tubes having substantially the same wall thickness so that all of said tubes can be compressed and simultaneously closed at points intermediate their lengths. respectively, along a common transverse line for the pumping operation, and means including a spring loaded platen having a pump tube supporting surface and a plurality of rollers engageable with said tubes for simultaneously compressing the tubes progressively along their lengths against said surface of said platen for the pumping operation; a pair of longitudinally extending laterally spaced members removably mounted on said surface of said platen, said members having roller engaging surfaces spaced from said surface of said platen a distance equal to approximately twice the wall thickness of said tubes for limiting the position of said rollers relative to the surface of said platen during the closed condition of said tubes and thereby limiting the compression load of said rollers on said tubes when said tubes are closed during said pumping operation, and means for providing addi- A tional spring pressure on said platen for increasing the tube closing pressure of said rollers on said tubes.

3. In a pump having a plurality of resiliently flexible pump tubes disposed laterally of each other for the delivery of a plurality of fluids in predetermined relative proportions, said tubes having substantially the same wall thickness so that all of said tubes can be compressed and closed simultaneously at points intermediate their lengths, respectively, along a common transverse line for the pumping operation, and means including a platen having a pump tube supporting surface and a plurality of rollers engageable with said tubes for simultaneously compressing and closing the tubes progressively along their lengths against said surface of said platen for the pumping operation; a frame mounted on said platen surface and comprising a pair of longitudinally spaced end blocks for retaining said tubes in position on said platen surface, and a pair of laterally spaced side members extending between said end blocks and connected to said end blocks at the ends of said side members, said side members having roller engaging surfaces spaced a predetermined distance from said surface of said platen for limiting the position of said rollers relative to said platen surface during the closed condition of said tubes and thereby limiting the compression load of said rollers on said tubes when said tubes are closed during said pumping operation.

4. In a pump having a plurality of resiliently flexible pump tubes disposed laterally of each other for the de livery of a plurality of fluids in predetermined relative proportions, and means including a spring loaded platen having a tube supporting surface and a plurality of rollers engageable with said tubes for simultaneously compressing and closing the tubes progressively along their lengths against said surface of said platen for the pumping oper ation; a pair of laterally spaced members mounted on said platen, said members having roller engaging surfaces spaced from said surface of said platen a distance equal to approximately twice the wall thickness of said tubes for limiting the position of said rollers relative to the surface of said platen during the closed condition of said tubes and thereby limiting the compression load of said rollers on said tubes when said tubes are closed during said pumping operation, and means for providing additional spring pressure on said platen for increasing the tube ciosing pressure of said rollers on said tubes.

5. In a pump having a plurality of resiliently flexible pump tubes disposed laterally of each other for the delivery of a plurality of fluids in predetermined relative proportions, said tubes having substantially the same wall thickness so that all of the said tubes can be compressed and simultaneously closed at points intermediate their lengths, respectively, along a common transverse line for the pumping operation, and means including a platen having a supporting surface for a plurality of said tubes disposed in side-byside relation on said surface, and a plurality of transversely extending rollers engageable with said tubes and movable longitudinally of said tubes for simultaneously compressing the tubes progressively along their lengths against said surface of said platen for the pumping operation; means on said platen for limiting the compression load of said rollers on said tubes during the closed condition thereof, said last mentioned means comprising longitudinally extending members spaced laterally of each other, said members having roller engaging surfaces extending longitudinally of said tubes when said tubes are supported on said surface of the platen, said roller engaging surfaces of said members being spaced a predetermined distance from said surface of said platen for limiting the movement of said rollers toward said surface of said platen during the closed condition of said tubes to thereby limit the compression load of said rollers on said tubes when said tubes are closed during said pumping operation.

6. In a pump having a plurality of resiliently flexible pump tubes disposed laterally of each other for the delivery of a plurality of fluids in predetermined relative proportions, said tubes having substantially the same wall thickness so that all of said tubes can be compressed and simultaneously closed at points intermediate their lengths, respectively, along a common transverse line for the pumping operation, and means including a platen having a supporting surface for said tube and a plurality of trans versely extending rollers engageable with said tubes and movable longitudinally of said tubes for simultaneously compressing the tubes progressively along their lengths against said surface of said platen for the pumping operation, means for limiting the compression load of said rollers on said tubes during the closed condition thereof comprising a pair of longitudinally extending members spaced laterally of each other and removably mounted on said surface of said platen along the marginal side edges thereof, said members having roller engaging surfaces positioned for engagement by said rollers adjacent the opposite ends, respectively, of said rollers and spaced a predetermined distance from said surface of said platen for limiting the position of said rollers relative to said platen surface during the closed condition of said tubes and thereby limiting the compression load of said rollers on said tubes when said tubes are closed during said pumping operation.

7. In a pump having a plurality of resiliently flexible pump tubes disposed laterally of each other for the delivery of a plurality of fluids in predetermined relative proportions, said tubes having substantially the same wall thickness so that all of said tubes can be compressed and simultaneously closed at points intermediate their lengths, respectively, along a common transverse line for the pumping operation, and means including a platen having a supporting surface for said tubes and a plurality of transversely extending rollers engageable with said tubes and movable longitudinally of said tubes for simultaneously compressing the tubes progressively along their lengths against said surface of said platen for the pumping operation, said platen having pins positioned at the opposite ends of said platen and extending upwardly from said surface thereof, and pump tube holding means positioned at each of said ends of said platen and removably mounted on said pins for holding said pump tubes in position on said surface; means for limiting the compression load of said rollers on said tubes during the closed condition thereof comprising a pair of longitudinally extending members spaced laterally of each other and removably mounted on said surface of said platen along the marginal side edges thereof, each of said members having apertures at its opposite ends through which said pins extend for removably holding said members in said mounted position thereof on said surface, said members having roller engaging surfaces positioned for engagement by said rollers adjacent the opposite ends thereof and spaced a predetermined distance from said surface of said platen for limiting the position of said rollers relative to said platen surface during the closed condition of said tubes and thereby limiting the compression load of said rollers on said tubes when said tubes are closed during said pumping operation.

References Cited in the file of this patent UNITED STATES PATENTS 213,032 Betts Mar. 11, 1879 245,665 Scott Aug. 16, 1881 1,924,973 Beede et al. Aug. 29, 1933 1,956,108 Symington et al Apr. 24, 1934 2,804,023 Lee Aug. 27, 1957 2,893,324 Iseeli et al. July 7, 1959 2,933,311 Spak Apr. 19, 1960 

1. IN A PUMP HAVING A PLURALITY OF RESILIENTLY FLEXIBLE PUMP TUBES DISPOSED LATERALLY OF EACH OTHER FOR THE DELIVERY OF A PLURALITY OF FLUIDS IN PREDETERMINED RELATIVE PROPORTIONS, SAID TUBES HAVING SUBSTANTIALLY THE SAME WALL THICKNESS SO THAT ALL OF SAID TUBES CAN BE COMPRESSED AND SIMULTANEOUSLY CLOSED AT POINTS INTERMEDIATE THEIR LENGTHS, RESPECTIVELY, ALONG A COMMON TRANSVERSE LINE FOR THE PUMPING OPERATION, AND MEANS INCLUDING A SPRING LOADED PLATEN HAVING A PUMP TUBE SUPPORTING SURFACE AND A PLURALITY OF ROLLERS ENGAGEABLE WITH SAID TUBES FOR SIMULTANEOUSLY COMPRESSING THE TUBES PROGRESSIVELY ALONG THEIR LENGTHS AGAINST SAID SURFACE OF SAID PLATEN FOR THE PUMPING OPERATION; A PAIR OF LATERALLY SPACED MEMBERS MOUNTED ON SAID PLATEN, SAID MEMBERS HAVING ROLLER ENGAGING SURFACES SPACED FROM SAID SURFACE OF SAID PLATEN A DISTANCE EQUAL TO APPROXIMATELY TWICE THE WALL THICKNESS OF SAID TUBES FOR LIMITING THE POSITION OF SAID ROLLERS RELATIVE TO THE SURFACE OF SAID PLATEN DURING THE CLOSED CONDITION OF SAID TUBES AND THEREBY LIMITING THE COMPRESSION LOAD OF SAID ROLLERS ON SAID TUBES WHEN SAID TUBES ARE CLOSED DURING SAID PUMPING OPERATION, AND MEANS FOR PROVIDING ADDITIONAL SPRING PRESSURE ON SAID PLATEN FOR INCREASING THE TUBE CLOSING PRESSURE OF SAID ROLLERS ON SAID TUBES. 